Reversible feed mechanism for machine guns



April 25, 1950 J. L. LOCHHEAD 2,504,994

' REVERSIBLE FEED MECHANISM FOR MACHINE GUNS Original Filed Oct. 50, 1942 L'l lllllllllllllln HELL Jrwmvtoc 3) Llmhn Limchhead mm vwm Patented Apr. 25, 1950 REVERSIBLE FEED MECHANISM FOR MACHINE GUNS John L. Lochhead, Springfield, Mass., assignor to the United States of America as represented by the Secretary of War Original application October 30, 1942, Serial No. 463,880. Divided and this application August 31, 1944, Serial No. 552,115

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 3 Claims.

The invention described herein may be manufactured and used by or for the Government for governmental purposes, without the payment to me of any royalty thereon.

This invention relates to improvements in reversible feed mechanism for machine guns. This application is a division of my copending appli cation Serial No. 463,880 filed October 30, 1942, U. S. Patent No. 2,425,749, dated August 19, 1947.

Present day machine guns used in aircraft or tanks may be fired with either right or left hand feeding of the ammunition into the gun. The conventional way of accomplishing feeding from either side of the gun is to provide a double cam track in the bolt of a machine gun such as disclosed in U, S. Patent No. 1,628,226 to John M. Browning. A stud provided on the belt feed lever follows the cam track in the bolt and a sideways motion thereby imparted to the belt feed lever is transmitted to the belt feed slide This is naturally an undesirable feature as these components may be improperly assembled or lost.

Considerable difficulty is also frequently encountered in present day machine guns when attempting to feed long, heavily loaded belts of ammunition. This is largely due to lack of power because of insufficient leverage of the conventional belt feed lever. Therefore a belt feeding mechanism which is readily converted to right or left hand feeding and which utilizes maximum mechanical advantage would be most desirable.

Accordingly, it is an object of this invention to produce an improved machine gun feeding action.

Another object of this invention is to provide a belt feed lever having a single cam track which can be readily used for right or left hand feeding of the gun without the necessity of additional components for such conversion.

A further object of this invention is to provide an improved belt feed lever to insure positive feeding of a heavily loaded belt of cartridges.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings in which:

Fig. l is a partial side elevational view of a machine gun, partly broken away to show the belt feed lever.

Fig. 2 is a top elevational view of Fig. 1 with 2 the cover partially broken away to feed lever.

In Fig. 1 there is shown a partial longitudinal sectional view of a machine gun such as disclosed in U. S. Patent No. 1,628,226 to John M. Browning which embodies this invention. The gun as shown in Fig. 1 comprises mainly a receiver I, a trunnion 2, and a cover 3. Slidably mounted within the receiver l is a bolt 2, a barrel l3, and a barrel extension E l. A belt feed lever 15 is pivotally mounted on the cover 3. The belt feed lever I5 is a long fiat member having a narrow cam track 56 in the center thereof, here shown as a slot, (Fig. 2) which operates to impart a transverse movement to the lever l5 and hence to a belt feed slide or carrier 23 which is slidably mounted in the cover 3. The cam track It is defined by two oppositely disposed sides I? show the belt I and It of the belt feed lever l5 which conform generally in shape to the cam track it. One end of the belt feed lever l5 projects forwardly to form a rounded end it. The end is fits between two centrally-located integral upwardly projecting lugs 24 and 25 provided on the belt feed slide 23. On the other end 28 of the belt feed lever it an outwardly projecting lug 2i is provided. A hole 22 is centrally provided in the projection 2! to mount the lever on the cover 3 by a bolt 26. The bolt 25 is inserted through either of a suitable vertical hole 5 or 5 in the cover 3 and the bolt is secured to the cover 3 by a nut 21. A cotter pin 28 inserted in a suitable hole in the nut 21 and the bolt 26 prevents the nut 21 from unscrewing.

The cover 3 is pivotally mounted on the top of trunnion 2 by a pin l. When cover 3 is closed, cam track It engages a stud 29 on bolt I so that belt iced lever l5 will be actuated directly by the reciprocating bolt to feed ammunition into the gun. The stud as is suitably secured in the .center of an integral upwardly projecting lug 8 provided on the forward upper surface of the bolt 1. To aid in reducing friction between the cam track is of the belt feed lever l5 and stud 29, a roller 31)- may be suitably mounted on stud 29.

The cycle of operation of the machine gun shown in Fig. 1 is similar to that disclosed in the previously mentioned patent to John M. Browning. The bolt 1 reciprocates in a. straight line within the receiver after the discharge of each cartridge. With the cover 3 in a closed position, the cam track 16 engages the stud 29 of the bolt 1 as previously mentioned. As the belt feed lever 'levera;

I5 is pivoted at end 20, the free end it of the lever l5 will describe a path of motion the length of which is determined by the length and shape of cam track Hi. In order to feed the belt of ammunition into the gun, the slide 23 will of course have to reciprocate within the cover a and will have to be so timed that it will introduce a cartridge when the bolt comes into battery position.

It is obvious, therefore, that the actuating movement of lever and thefeeding movement of belt feed slide 23 will have to be just the opposite for right hand feeding as for the position of left hand feeding shown inlFig. 2. To accomplish this reversal in feeding, it is necessary to unfasten the pivoted end of the belt feed lever 15, invert the lever about its longitudinal axis, and reassemble it to covert but this time using hole 6 as the pivot point. Beltfeedslide 23 need not be reversed, however, since end as of lever .15 will ,fit between centrally-located lugs 2d and 25 in either position. Since cam track [6 will now curve to the left, slide 23 will be actuated to theright and back again as bolt I recoils and counter-recoils. It should also be understood, that the conventional pawl mechanism (here not shown) used to engage a round at the end of the outer stroke of slide 23 will have to be reversed from the left side of belt feed slide 23 to theright, side. Thus by the use of this belt feed lever costly machining operations on the bolt by eliminationof the duplicate cam track and elimination of other related components is eifected.

As previously stated, difficulty is sometimes experienced with the conventional form of belt feed leverinfeeding a heavily loaded belt of ammunition into the gun.

This may be inlarge part attributed to the method of mounting the belt feed lever. As the conventional lever is pivoted approximately in the center, the lever arm from the center of the lever to the end thereof is comparatively short so that on the feeding stroke of the bolt, where the greatest the cover at-its rear end instead of in the center.

Thus it is readily apparent that as the bolt approaches'the battery position the lever arm increases in length at the point where the greatest is needed. Because of the added leverage ai'forde'd by this belt feed lever, feeding difficulties normally encountered with a machine gun of the type disclosed in the aforementioned patent are readily overcome.

I claim:

1. In a belt fed machine gun having a reciprocating bolt and a transversely reciprocating belt carrier, the improvement comprising, in combination, a unitary longitudinal belt feed lever pivotally :mounted at one end adjacent the :rear of the :gun and having the other end directly engaged bythe belt carrier, said lever having a cam slot therein, and means on the forward end of the reciprocating bolt engaged in said cam slot, :all constructed and arranged whereby saidfeed lever is pivoted in one direction during the rearward travel of the .bolt and ill ' combination, a

4 pivoted in the opposite direction during the forward travel of the bolt.

2. In a belt fed machine gun having a reel-procating bolt and a transversely reciprocating belt carrier, the improvement comprising, in unitary longitudinal belt feed lever pivotally mounted at one end adjacent the rear of the gun, a forwardly extending integral projection on the other end of said lever, a pair of parallel lugs on the belt carrier defining a slot therebetween adapted to continuously engage said lever projection, said lever having a cam slot extending longitudinally therein, and a roller horizontally mounted on the forward end of the reciprocating bolt, said cam slot being constructed and arranged to continuously engage said roller whereby said belt feed lever is pivoted in one direction during substantially the first half of the rearward travel of the bolt and pivoted in the opposite direction during substantially the second half of the forward travel of the bolt thereby transversely reciprocating the belt carrier to feed a belt of ammunition into the gun.

3. In a belt fed machine gun having a reciprocating bolt and a transversely reciprocating belt carrier, the improvement comprising, in combination, a unitary longitudinal belt feed lever pivotally mounted at one end in one of two selective positions at the rear of the gun, said lever being reversed about a longitudinal axis upon changing from one of said selective positions to the other, a forwardly extending integral projection on the other end of said lever, a pair of parallel lugs on the belt carrier defining a slot therebetween adapted to receive said projection in either of said two selective positions, said lever having a cam slot extending longitudinally therein, and a stud on the for-- ward end of the reciprocating .bolt arranged to follow the track of said cam slot, all constructed and arranged whereby the pivoting of said feed lever when mounted in either of said two sele tive positions reciprocates the belt carrier to feed a belt of ammunition into one side of the gun and when reversibly mounted in the other of said two selective positions reciprocates the belt carrier to feed from the opposite side of the gun.

JOHN L. LOCI-IHEAD.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 430,210 Maxim, June 17, .1890 723,719 North Mar. 24, 1903 1,625,994 Gorton Apr. 26, 1927 1,695,508 Skinner et a1 "Dec, 18, 192.8

1,803,3 l9 Pfeiffer May 5, 1931 FOREIGN PATENTS Number Country Date 141,955 Austria June 11, 1935 692,291 Germany June 15, 1940 OTHER. REFERENCES Instruction Manual for the MG 42 (Ger) Mar. 15, 1943. 

